Re: [OSPF] PHP route determination in draft-ietf-ospf-segment-routing-extensions-03

[Santanu Kar <[e-mail]>]

Hi Peter

I think, considering we are using Ext Prefix LSA in 'Area-Flooding' scope, A
should do PHP for 20.1.1.0/24  if C has advertised it.
If  A doesn’t pop for 20.1.1.0/24, and give the packet to B, it will drop
it, since PHP is enabled by default for all nodes.

Regards
Santanu

-----Original Message-----
From: Peter Psenak [mailto:[e-mail]]
Sent: Thursday, April 02, 2015 1:08 PM
To: Santanu Kar; [e-mail]; [e-mail]; [e-mail];
[e-mail]; [e-mail]; [e-mail]
Subject: Re: PHP route determination in
draft-ietf-ospf-segment-routing-extensions-03

Santanu,

If B is not advertising a SID for 20.1.1.0/24, then A will not do PHP.

regards,
Peter


On 4/2/15 08:39 , Santanu Kar wrote:
> SANTANU> Iactually wanted to highlight the non-ABR cases here.
> SANTANU> Consider
> the3routers below,in same area.
>
>   A -----10.1.1.0/24----- B ------20.1.1.0/24 -----C
>
> In thecontext of A, the route of 20.1.1.0/24 <http://20.1.1.0/24> is a
> PHP route. Now the Prefix Segment for prefix 20.1.1.0/24
> <http://20.1.1.0/24> can be advertised by bothB, as well as by C
> towards A. The case I am considering here is, C has advertised the
> prefix segment of 20.1.1.0/24 <http://20.1.1.0/24> to Afirst.Stillwhen
> A is calculating label for20.1.1.0/24 <http://20.1.1.0/24>,it should
> take it as PHP. Howeverthe text in draft states "upstream neighbor of
> the Prefix-SID originator MUST pop the Prefix-SID". Here A is not the
> upstream neighbor of C.
>

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